Assume there are two lists A=[[1,2,3],[4,5,6],[7,8,9],[10,11,12]] and B=[[1,2,3],[5,6,4],[7,1,9]]. I want to compare these two lists and return
A=[[1,2,3],[4,5,6],[7,8,9],[10,11,12]]
B=[[1,2,3],[5,6,4],[7,1,9]]